Fig. 3From: From non-targeted to targeted GC–MS metabolomics strategy for identification of TCM preparations containing natural and artificial muskChemical structures of the two chemical markers (A). Histogram (B) of the peak area in two markers. Principal component analysis (C) and orthogonal partial least-squares discrimination analysis (D) of prasterone and androstone in natural musk (green) and artificial musk (blue)Back to article page